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Low-Cost Electronic Microwave Calibration for Rapid On-Line Moisture Sensing of Seedcotton
United States Department of Agriculture, Agricultural Research Services, Lubbock, TX 79403, USA
Sensors Group Microsemi Corporation Lowell, MA 01851, USA
* Author to whom correspondence should be addressed.
Received: 10 October 2010; in revised form: 11 November 2010 / Accepted: 15 November 2010 / Published: 6 December 2010
Abstract: In order to improve rapid on-line moisture sensing of seedcotton in cotton gins, a means by which to establish a reliable low-cost wide-band electronic calibration is critically needed. This calibration is needed to center the circuit due to changes in the internal signal delays and attenuation drift caused by temperature changes in the various system components and circuit elements. This research examines a hardware technique for use in conjunction with microwave reflective sensing probes having an extended bandwidth from 500 MHz through 2.5 GHz. This new technique was validated experimentally against known electrical propagation delay standards. Results of the measured propagation delay with this type of automatic electronic calibration method was found to agree with results using a vector network analyzer with a traditional S11 single port error correction calibration methodology to within 4% of the measurement, 95% confidence, with a standard error of +/−18.6 ps for the delay measurements. At this level of performance, the proposed low-cost technique exhibits superior performance, over the typical geosciences time-domain reflectometer “TDR”, instruments in common use in soil moisture testing and is suitable for use in cotton gin moisture sensing.
Keywords: cotton; moisture; sensing; microwave
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MDPI and ACS Style
Pelletier, M.G.; Viera, J.A. Low-Cost Electronic Microwave Calibration for Rapid On-Line Moisture Sensing of Seedcotton. Sensors 2010, 10, 11088-11099.
Pelletier MG, Viera JA. Low-Cost Electronic Microwave Calibration for Rapid On-Line Moisture Sensing of Seedcotton. Sensors. 2010; 10(12):11088-11099.
Pelletier, Mathew G.; Viera, Joseph A. 2010. "Low-Cost Electronic Microwave Calibration for Rapid On-Line Moisture Sensing of Seedcotton." Sensors 10, no. 12: 11088-11099.